1. Field Of The Invention
The present invention relates to film welded reservoir bags with seam structure, of a type useful in breathing circuits, and to a novel method of making such reservoir bags.
2. Description of the Related Art
Breathing circuits are commonly used for anesthesia administration, pulmonary treatments such as administration of lung surfactants to neonatal patients, delivery of therapeutic agents such as pentamidine to the alveoli of the lungs, etc., and oxygen administration.
Such breathing circuits typically incorporate a gas source or other supply for the medicament or treatment agent, e.g., a nebulizer or entrainment device for introducing the therapeutic agent into a gas stream for delivery to the patient, together with waste gas or contaminant removal means such as chemisorbents (scavengers) or physical adsorbents, which may for example remove CO2 from the breathing circuit. A mask or intubating conduit may be utilized in the circuit for delivery of the treatment gas to the patient.
The breathing circuit also variously includes reservoir bags, sometimes termed ventilator bags. The function of such bags is to provide a hold-up or expansion volume that may be selectively (manually or automatically) compressed to cause flow of the treatment gas to the patient.
Conventional reservoir bags are formed of latex and available in differing sizes (e.g., 1, 2 and 3 liter volumes). Conductive latex is frequently used in circumstances where the treatment gases are flammable in character.
Latex bags of such type are formed by dip-molding processes, in which a mandrel is dipped into a latex bath to coat the mandrel with a thin film of the latex material, followed by drying and curing of the latex and removal of the bag article from the mandrel. Such latex bags are seamless in character.
Although latex reservoir bags are readily produced in large volume at relatively low cost, they suffer the disadvantage, common to latex generally, that a significant portion of the population experiences allergic or antigenic reactions in exposure to latex. For this reason, it is desirable to provide a reservoir bag of non-latex construction, to obviate the risk and danger associated with latex.
Non-latex breathing bags are known, however, all of such bags are made by dip-molding processes and are seamless, which means that such materials must have an elongation of at least 1000% to accommodate demolding (removal) from the mandrel on which the bag is formed.
Unfortunately, there exist few non-latex materials that have elongation in excess of 1000% and are suitable for dip-molding. Such materials include synthetic latex materials, polyisoprene, nitrile rubbers and silicones, but such materials are relatively expensive in relation to latex and/or have other deficiencies that have limited their commercial use for reservoir bag fabrication.
The present invention relates to a bag with seam formed by welding of two layers of film of non-latex material and having application as a breathing circuit component.
In one aspect, the invention relates to a pulmonarily sized bag formed of a non-latex material, comprising a bag body formed of panels of resin film material welded to one another along a weld line defining a seam of the bag body bounding an interior volume of the bag, wherein the seam comprises an interior seam portion in the interior volume, and an exterior seam portion at an exterior surface of the bag, and wherein one of the interior seam portion and exterior seam portion comprises free edges of the seam, and wherein the other of the interior seam portion and the exterior seam portion at the exterior surface of the bag is devoid of free edges.
In another aspect, the invention relates to a method of forming a pulmonarily sized bag, comprising superpositioning sheets of a non-latex material on one another, welding the superpositioned sheets to one another along a weld line defining the shape of the bag and forming a seam comprising free seam edges, thereby producing a welded article.
Other aspects, features and embodiments of the invention will be more fully apparent from the ensuing disclosure and appended claims.